100 ^HE EVOLUTION OF PLANTS 



leaves in some cases and their venation in others, 

 the leaf-like, stem-borne sporophylls of the 

 female Cycas, are all characters which recall 

 the Ferns. The Bennettitese, advanced as they 

 were in many ways, yet in some respects ap- 

 proached the Ferns even more nearly than the 

 Cycadacese, notably in their extraordinary com- 

 pound stamens, so closely resembling the fertile 

 fronds of a Marattia (see p. 147), and in the 

 presence of a dense covering of flat scaly hairs, 

 like the chaffy coat which clothes the young 

 fronds of our present-day Ferns. It is probable 

 that, as our knowledge extends, the resem- 

 blance will turn out to go further, for there are 

 a number of Mesozoic fronds as to which it is 

 still quite uncertain whether they belonged to 

 Ferns or Cycads. 



Our object is now to trace the Cycadophyta 

 further back, and to see whether the Palaeozoic 

 rocks reveal anything of then* evolution. If 

 we can succeed in this quest, we shall clearly 

 have made a long step towards finding the origin 

 of the Seed-plants generally, for the Cycadophyta 

 were not only of immense importance in the 

 middle period of geological history, but, as we 

 have seen, were the probable source of the now 

 dominant race of Flowering Plants. The sub- 

 ject we have now to consider is thus of even 

 wider scope than the origin of the Angiosperms, 



